Changes in acute skeletal muscle oxygenation and blood flow in trained and untrained males during 10RM resistance protocol measured by NIRS
Date
2002
Authors
Harrison, David Michael
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Abstract
The purpose of this study was to observe muscle oxygenation and blood volume changes and half time to full 0 2 saturation elicited by 1 ORM biceps exercise in trained (ages 23.8 ± 3.5 years, sum of 4 arm skinfolds 15.2 ± 3.7 mm, arm girth 35.7 ± 3.0 cm) and untrained subjects (ages 25.3 ± 3.6 years, sum of 4 arm skinfolds 16.6 ± 3.2 mm, arm girth 28.4 ± 3.1 cm). 22 males volunteered for the study and were self-assigned to a trained (N= l 3) or untrained (N=9) group based on training experience. Each subject completed 3 sets of a 1 ORM exercise protocol using biceps curls, and a base-line muscle ischaemia protocol on separate days that were randomly determined. Blood volume, tissue oxygenation and half-time to full 0 2 saturation of the right biceps brachii muscle were monitored non-invasively using a near-infrared spectrophotometer (NIRS) in both protocols. The NIRS probe was positioned approximately at the mid-point of the belly of the biceps brachii muscle. Both the trained and untrained subject groups showed decreases in blood volume and tissue oxygenation during each set of exercise of the lORM protocol. No set-wise differences were seen within the trained and untrained subject groups during the 3 sets of right arm biceps curl exercise at a load of 1 ORM. In addition, no differences were seen between trained and untrained groups in a set-wise comparison of muscle oxygenation and blood volume. However, a statistical significant difference was seen between the group mean percentage change in muscle oxygenation of the untrained subject group and the warm-up set and the 3 sets of 1 ORM for the trained subject group. No set-wise differences were found within the trained and untrained subject groups in the half-time to full 02 saturation during the exerci se protocol. In addition, no differences were seen between trained and untrained groups in a set-wise comparison of the half-times to full 02 saturation. It was concluded that blood volume and oxygenation decrease during resistance exercise but the decrease appears to be independent of the training status of the subjects.